Lens grinding machine



Oct. 17, 1939. J. SHANNON 2,176,154

LENS GRINDING MACHINE Filed Dec. 1,1936 4 sheets-sheet 1 ATTO R N EYSOct. 17? 1939. Jl SHANNON 2,176,154

LENS GRINDING MACHINE Filed Dec. l, 1936 4 Sheets-Sheet 2 QZQQT 18 ,95KQE?? INVENTOR ATTORNEYS Oct. 17, 1939. SHANNON 2,176,154

LENS GRINDING MACHINE Filed Deo. l, 1936 4 Sheets-Sheet 3 In! all!!INVENTOR Mmes BY ATTORNEYS oct. 17, 1939. J. SHANNON 2,116,154

LENS GRINDING MACHINE Filed Dec. l, 1936 4 Sheets-Sheet 4 sa" foe@/ZQZ/Zofz INVENTOR gay@ 56, BY @4% ATTORNEYS Patented Oct. 17, 1939UNlTED STATES PATENT oFFicE 3 Claims.

My invention relates to improvements in grinding and polishing machinesfor producing cylinder lenses.

In machines of this class, as usually constructed, a work support orlens holder and a grinding tool commonly called a lap member, are movedeither relatively, or, one with respect to the other, to effect thegrinding and polishing operation. The character and direction of move-Ll)v ments Varies in different makes of machines with more or lesssatisfactory results but within a limited range or eld of operation asregards the cylinder diopters which such machines are capable ofgrinding and polishing accurately on a lens. Moreover, in machines ofthis class known to me, vibration is excessive, particularly under highspeed operation, and frequently results in inaccurately or imperfectlyground lenses.

Z Having the foregoing in mind, the primary object of my invention is toprovide a high speed lens grinding and polishing machine having a widerrange of operation than machines heretofore devised for this purpose andin which vibration has been reduced to a negligible degree to render themachine accurate in the high speed operation thereof.

Another object is to provide a machine of the class and for the purposeabove set forth adapted 50 for simultaneously grinding and polishing apair of lenses concave and convex,.respectively.

Still another object is to provide a high speed machine forsimultaneously driving a lens holder and a lap member over a lap memberand a lens 55 holder, respectively, each in different zig-zag paths andwith related holders and lap members always in proper axial relation foraccurate cylinder grinding.

Still another object is to provide for so-called L0 cap grinding andpolishing lenses by movement of a lap member thereover, in a zig-zagpath in co-axial relation to the lens and for oscillating the lens witha Variable throw to produce surfaces of different cylinder diopters onsaid lenses.

Other and subordinate objects are also comprehended by my invention, allof which, together with the exact nature of my improvements, will beunderstood as the following description proceeds and upon reference tothe drawings accompanying and forming part of the specification.

In said drawings:

Figure 1 is a view in top plan of a machine embodying my improvements.

'tai

Figure 2 is a View in transverse section taken.

on theline 2 2 of Figure 1 looking in the direction indicated by thearrows.

Figure 3 is a fragmentary view of part of a pitman drive for themachine.

Figure 4 is a similar View of another similar 5 drive with which themachine is equipped.

Figure 5 is a view in transverse section taken on the line 5 5 of Figure4 looking in the direction indicated by the arrows.

Figure 6 is a View in longitudinal section taken 10 on the line 6 6 ofFigure 1 looking in the direction indicated by the arrows.

Figure 7 is a View in transverse section taken on the line 1 1 of Figure1 looking in the direction indicated by the arrows.

Figure 8 is a similar View taken on the line 8 8 of Figure 1.

Figure 9 is a View in horizontal section taken on the line 9 9 of Figure1 looking in the direction of the arrows.

Figure 10 is a similar view taken on the line l0 lll of Figure 1.

Figure 11 is another similar View taken on the line H II of Figure 1.

Figure l2 isV a detail View in top plan of a 25 reciprocatoryl carriageand an oscillating carriage thereon forming part of the drive mechanismof the machine.

Figure 13 is a fragmentary View in tcp plan of a sleeve member and ashaft forming part of the b reciprocatory carriage.

Figure 14 is a view in top plan-of a rocker arm forming part of theoscillating carriage.

Figure l5 is a view in transverse section taken on the line IE5-l5 ofFigure l of a convex lens 3 driving unit.

Figure 16 is a similar view illustrating the operation of said unit.

Figure 17 is a fragmentary View in side elevation of a portion of saidunit.

Figure 18 is a view in transverse section of a A cap grinding andpolishing unit.

Figure 19 is a similar fragmentary View illustrating the parts of saidunit in their normal position.

Figure 20 is a view in sideV elevation of the part shown in Figure 19;

Figure 2l is a detail view in section further illustrating the operationof the convex grinding unit. Y

Figure 22 is a similar view illustrating the corresponding position inthe operation of the machine of the cap polishing and grinding unit.

Figure 23 andk 24 are detail views of bearingsY for said units. 55,

Figure 25 is a diagrammatic view illustrating the operation of the unit,and

Figure 26 is a similar View further illustrating the operation of thecap grinding unit.

Referring to the drawings by numerals, the illustrated embodiment of myinvention comprises concave and convex grinding units I and 2respectively, the former, a so-called cap grinding and polishing unit.The two units are arranged side by side on a base 3. The grinding unit Icomprises a lens support 4, of the usual type, mounted on said base 3,in a manner presently described in detail, and a lap member 5surmounting the support 4. The support 4 is shown with a lens 5 cementedtherein according to the usual way of mounting the lens in the supportmember The grinding unit 2 comprises a lap member 1 mounted n the base3, in a manner presently described, and a lens support or carrier 8surmounting the lap member 1. The lens 8' is cemented to the support orcarrier 8 as shown in Figure 21.

The lap member of the unit I and the lens carrier 3 of the unit 2 aremounted in separate frames 9 and le, respectively, disposed side by sidein parallel relation and each comprising a rectangular head part II anda rearwardly extending shank part I2. The manner in which the lap member5 and the lens carrier 8 are mounted in their respective frames, 3 andI8, will presently be referred to in detail. The frames 9 and IE! aremounted on a horizontally reciprocating carriage I3 for reciprocation inunison. The carriage I3 comprises a sleeve I4 having a rearwardlydisposed V-shaped extension I5. The sleeve I4 is slidably mounted, onbearing bosses I6, on a horizontally disposed shaft I1 xed at itsopposite ends in brackets I8 arising from the base 3. Set collars I9 onsaid shaft I1 and set screws 20 in the brackets I8 secure said shaft inposition in said brackets. The shaft I1 is bored axially andtransversely, as at 2| and 22 respectively, for the introduction of oilthrough said shaft into the sleeve I4. The extension I5 of the carriageI3 is pivotally mounted by means of a cone bearing stud 23, on a link 24opposed to the sleeve I4 and pivotally mounted at its opposite ends on apair of oppositely disposed rocker arms 25 and 26 pivoted on the base 3and a bearing bracket 21, respectively, as by pivot bolts 28. Thearrangement of the link 24 and the rocker arms 25 and 28 is such thatthe link 24 moves substantially parallel with the sleeve I4.

The carriage I3 is driven from a main drive shaft 29 journaled adjacentits opposite ends, parallel with the shaft I1, in bearing brackets 3Usecured to the base 3 in any suitable manner. The main shaft 29 isdriven through the medium of a belt and pulley drive, indicated at 3Iand 32, by a suitable motor (not shown). A worm 33 fast on the maindrive shaft 29 meshes with a worm wheel 34 fast on a short shaft 35journaled in bearings 35 on the base 3. The short shaft 35 isoperatively connected to the carriage I3 by means of a pitman drivecomprising a disc 31 fast on said shaft and a pitman rod 38 connected toa lug 39 on the sleeve I4. The connection between the pitman rod 38 anddisc 31, as shown in Figures 3 and 5, comprises an eccentric 4Qadjustable in a strap 4I for varying the throw of the rod 31, as will beunderstood.

The frames 9 and I!! are mounted on the carriage I3 for oscillationthereon transversely of their paths of reciprocation by said carriage,in curved paths, respectively, and in opposite directions relative toeach other. For this purpose the shank parts I2 of said frames aremounted, by means presently described, on a horizontally disposedoscillating carriage 42. The oscillating carriage 42 comprises a pair ofV-shaped yokes 43 pivoted, as at 44, upon the opposite ends of a pair ofsubjacent parallel links 45 which in turn are pivoted intermediate theirends, as at 46, on a rocker 41. The rocker 41 is pivotally mounted onthe carriage I3 between a cone bearing stud 48 on the sleeve I4 and thebeforementioned cone bearing stud 23, the arrangement of the rocker 41being such that the oscillating carriage 42 has a compensating rockingmovement vertically about an axis at a right angle to its axes ofoscillation.

The carriage 42 is oscillated by means of a yoke member 48 pivotallymounted, as at 50, on the base 3 for vertical rocking movement inbearings 5I, on the base 3, and to which the main drive shaft 29 isoperatively connected by means of a pitman drive including a disc 52fast on said shaft and a connecting rod 53 extending between said discand the yoke. A second yoke member 54 is pivotally mounted, as at 55, onthe yoke 49 for vertical rocking movement with the yoke 49 and forindependent rocking movement laterally about an axis at a right angle tothe common axis of movement of said yoke. The yoke 54 is operativelyconnected to one of the links 45 of the carriage 42 by means of a rod 55extending from said link and a ball and socket connection 56 betweensaid rod and the yoke 54. The socket part of the connection 56 comprisesa section 51 adjustable in the yoke 54 by means of a set screw 58 totake up wear in the connection and for coupling said connectiontogether. As will be seen, the carriage 42 oscillates arcuately duringits reciprocation by the carriage I3. The yoke 54 operates in itsindependent movement to compensate for such reciprocation duringoscillation of said carriage 42. In this connection it is to be notedthat the axis of movement of the rocker 41 provides for compensatingmovement of the carriage 42 under the throw of the yoke 54 during suchindependent movement thereof.

The lap member 5 and the lens carrier 8 are mounted in the heads II oftheir respective frames, 9 and I0, for swinging movement in the generaldirection of oscillation of said frames and as follows. The head I I ofeach each frame, 9 and I U, is provided on its under side with a pair ofopposed needle bearings 59. Co-operating with the bearings 59 of eachhead II is a yoke bar 60 having angular ends 6I adapted to seat againstsaid bearings and rock thereon. The lens carrier 8, or the lap member 5,as the case may be, is secured to the under side of said yoke barintermediate its ends. In the case of the lens carrier 8 a stud 62 onsaid carrier extends upwardly through the related yoke bar 60 and isadjustably secured therein by nuts 63. The lap member 5 is formedintegrally with its related yoke bar 60. A tensioned spring 64 connectedwith the front of each head II, as at 65, and to the base 3, as at 66,yieldingly retains the lenses 6 and 8 and the lap members 5 and 1 inengagement, shown in Figures 15 and 20, so that under oscillation of theframes 8 and I0 the lap member 5 and the lens 8' are caused to move intheir respective frames 9 and I0 concentrically of the lens 5 and thelap 1, respectively.

The frames 9 and I0 are mounted in their respective yokes 43 formovement of each about right-angularly related axes and as follows. TheShanks I2 are supported in their respective yokes 43 by means of bearingbrackets 61. The bearing brackets 6l are each pivotally mounted by conebearings 68 in their respective yoke 43 for vertical rocking movementabout a horizontal axis transverse to the direction of oscillation ofsaid yoke. The Shanks I2 of the frames 9 and l are pivotally mounted bysimilar bearings 69 in their respective brackets 61 for lateral movementof the frames 9 and I8 about horizontal axes extending substantially inthe direction of the oscillation of said frames. The cone bearings 68and 89 are each adjustable to take up wear and removable for replacementof parts. By virtue of the described means of mounting the frames 9 andI8 in the yokes 43, the lenses 6 and 8 and the lap members 5 and l,under the action of the springs 64, are maintained in axial relationduring reciprocation of the frames I2 by the carriage I3.

The lap member is provided with an aperture 'lll therein for introducingthe usual abrasive and grinding material into said lap member withoutlifting the lap member from 01T the lens 6.

In the case of the cap grinding and polishing unit l, the lens supportor carrier 4 is mounted for oscillation in the general direction ofoscillation of the lap member 5 and with a variable throw. For thispurpose the support 4, as shown in Figure 1l, is mounted for verticaladjustment on a horizontally disposed rocking yoke 1| mounted to rockvertically at its opposite ends lupon spherical bearings 72 on bearingbrackets 'I3 upstanding from the base 3. A pair of tension springs 14connected at their opposite ends to the yoke 'H and to the base 3, as at15 and T6, respectively, tension said yoke ll against movement from acentral position. The mounting for the support or carrier 4 on said yoke'Il comprises a shank Il depending from said support 4 and slidablymounted in a sleeve 'i8 on said yoke H for vertical adjustment of saidsupport to different set positions. A set screw 19 provides for lockingthe shank 11 and support 4 in different set positions. The yoke 'H isrocked in opposite directions respectively by a pitman drive 80comprising a pair of reduction gears 8| and 82, the former fast on thedrive shaft 29 and the latter mounted in a bearing bracket 83 on thebase 3. A pitman rod 84 connected at its opposite ends to a crank pin 85on the gear 82 and a crank arm 36 on the yoke 1I operatively connectssaid gearing to said yoke. The oscillating support 4 provides for movingthe lens 6 thereon into the lap member 5 so that uniform polishing maybe obtained in all meridians of a cylinder. By adjusting the support 4to different set positions, the throw of the lens thereon may be variedin accordance with the cylinder diopters to be polished. The shank Tl isprovided with the graduations 81, Figure 18, which may be appropriatelydesignated to indicate proper settings for the polishing of differentcylinder diopters.

From the foregoing it will be manifest that my invention provides amechanism for moving a lens carrier and a lap, relative to a lap and alens carrier, with both a reciprocating stroke and an oscillating stroketransverse to the line of movement of the reciprocating stroke, thereciprocating stroke being longer than the oscillating stroke.Preferably the relative timing of the oscillating and reciprocatorycarriage drives is approximately four to one, so that four oscillatingstrokes are effected to one reciprocating stroke'. The result of this isthat the lens carrier and the lap are moved across their related lenscarrier and lap in different zig-zag paths, as illustrated in Figures 25and 26. The short strokes, being in opposed curves, neutralize thevibration so that the machine is easy running at high speed. Byadjusting the oscillating support 4, the stroke on this side of themachine may be lengthened or shortened, in accordance with differentoperating requirements. In this connection it is to be noted that theframes 9 and I!) are always maintained parallel lengthwise, regardlessof the size of the oscillating strokes on different sides of themachine, and the lens and the lap carried by said frames prevented fromturning axially, which features provides for a high degree of lapaccuracy under all conditions.

The foregoing is a detailed description of a preferred embodiment of myinvention and it is believed that its operation and advantages will beclear therefrom without further explanation.

It is to be understood, however, that the present disclosure isillustrative rather than restrictive and that right is herein reservedto modifications of details described, and relations of parts, fallingwithin the scope of the claims appended hereto.

What I claim is:

l. A lens grinding and polishing machine comprising a base, a lenssupport, a lap member, a frame surmounting said support, a second framesurmounting said member, means for reciprocatir said frames, a pair ofV-shaped yokes connected one to each frame, means connecting said yokestogether whereby to effect simultaneous oscillation thereof, and meansconnected to at least one of said yokes to effect oscillation of saidyokes.

2. A lens grinding and polishing machine comprising a base, a lenssupport, a lap member, a frame surmounting said support, .a second framesurmounting said member, means for reciprocating said frames, a pair ofV-shaped yokes connected one to each frame, means connecting said yokestogether whereby to eifect simultaneous oscillation thereof, andoperating means connected to said yokes in such a manner that the degreeof oscillations may be varied relative to the reciprocation of saidframes.

3. A lens grinding and polishing machine comprising a base, a lenssupport, a lap member, a frame surmounting said support, a second framesurmounting said member, means for reciprocating said frames, a pair ofV-shaped yokes connected one to each frame, means connected to one ofsaid yokes for oscillation thereof, and means connected to theconvergent ends of said yokes whereby to efectvoscillation of the otherof said yokes coactive with the oscillation of said one yoke, theoscillation of said other yoke being reverse from the oscillation ofsaid one yoke.

JOSEPH SHANNON.

